/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.catalina;

import java.util.Iterator;

/**
 * <p>Abstract representation of a database of {@link User}s and
 * {@link Group}s that can be maintained by an application,
 * along with definitions of corresponding {@link Role}s, and
 * referenced by a {@link Realm} for authentication and access control.</p>
 *
 * @author Craig R. McClanahan
 * @since 4.1
 */
public interface UserDatabase {


	// ------------------------------------------------------------- Properties

	/**
	 * Return the set of {@link Group}s defined in this user database.
	 */
	public Iterator<Group> getGroups();

	/**
	 * Return the unique global identifier of this user database.
	 */
	public String getId();

	/**
	 * Return the set of {@link Role}s defined in this user database.
	 */
	public Iterator<Role> getRoles();

	/**
	 * Return the set of {@link User}s defined in this user database.
	 */
	public Iterator<User> getUsers();


	// --------------------------------------------------------- Public Methods

	/**
	 * Finalize access to this user database.
	 *
	 * @throws Exception if any exception is thrown during closing
	 */
	public void close() throws Exception;

	/**
	 * Create and return a new {@link Group} defined in this user database.
	 *
	 * @param groupname   The group name of the new group (must be unique)
	 * @param description The description of this group
	 */
	public Group createGroup(String groupname, String description);

	/**
	 * Create and return a new {@link Role} defined in this user database.
	 *
	 * @param rolename    The role name of the new role (must be unique)
	 * @param description The description of this role
	 */
	public Role createRole(String rolename, String description);

	/**
	 * Create and return a new {@link User} defined in this user database.
	 *
	 * @param username The logon username of the new user (must be unique)
	 * @param password The logon password of the new user
	 * @param fullName The full name of the new user
	 */
	public User createUser(String username, String password,
	                       String fullName);

	/**
	 * Return the {@link Group} with the specified group name, if any;
	 * otherwise return <code>null</code>.
	 *
	 * @param groupname Name of the group to return
	 */
	public Group findGroup(String groupname);

	/**
	 * Return the {@link Role} with the specified role name, if any;
	 * otherwise return <code>null</code>.
	 *
	 * @param rolename Name of the role to return
	 */
	public Role findRole(String rolename);

	/**
	 * Return the {@link User} with the specified user name, if any;
	 * otherwise return <code>null</code>.
	 *
	 * @param username Name of the user to return
	 */
	public User findUser(String username);

	/**
	 * Initialize access to this user database.
	 *
	 * @throws Exception if any exception is thrown during opening
	 */
	public void open() throws Exception;

	/**
	 * Remove the specified {@link Group} from this user database.
	 *
	 * @param group The group to be removed
	 */
	public void removeGroup(Group group);

	/**
	 * Remove the specified {@link Role} from this user database.
	 *
	 * @param role The role to be removed
	 */
	public void removeRole(Role role);

	/**
	 * Remove the specified {@link User} from this user database.
	 *
	 * @param user The user to be removed
	 */
	public void removeUser(User user);

	/**
	 * Save any updated information to the persistent storage location for
	 * this user database.
	 *
	 * @throws Exception if any exception is thrown during saving
	 */
	public void save() throws Exception;


}
